Method and apparatus for semi-continuous casting of hollow ingots and products resulting therefrom

Abstract

Methods and associated apparatus for semi-continuous casting of hollow ingots are described. In one embodiment a method for the semi-continuous casting of a metallic hollow ingot is provided. The method includes providing a mold that includes a mold center having an inner pipe and an outer pipe arranged to form an annular space for a cooling media and an outer mold, circulating a cooling media in the annular space, feeding a source material to the mold, heating the source material to produce a molten material, moving the mold center progressively downward relative to the outer mold, and solidifying the molten material to form a hollow ingot. Embodiments relating to an apparatus for semi-continuous casting of hollow ingots, and products resulting from the semi-continuous casting of hollow ingots are also described.

1. A method for semi-continuously casting hollow ingots comprising:
 providing a mold having a mold cavity formed between:
 a mold center having an inner pipe and an outer pipe arranged to form an annular space for a cooling medium; and 
 an outer mold; 
 
 circulating a cooling medium in the annular space; 
 feeding a source material into the mold cavity; 
 heating the source material to produce a molten material; 
 moving the mold center progressively downward relative to the outer mold; and 
 solidifying the molten material to form the hollow ingot. 
 
     
     
       2. The method of  claim 1 , wherein the mold center is moved progressively downward using a puller. 
     
     
       3. The method of  claim 1 , wherein the cooling medium is provided at substantially the base of the mold and the cooling medium flows up through the inner pipe and down through the annular space. 
     
     
       4. The method of  claim 1 , wherein the cooling medium is water or a sodium-potassium eutectic. 
     
     
       5. The method of  claim 1 , wherein the mold center is locked in place using a puller. 
     
     
       6. The method of  claim 1 , wherein the source material is heated by one or more electron beam guns, electroslag remelting, a plasma arc process, or one or more plasma torches. 
     
     
       7. The method of  claim 1 , wherein the outer pipe remains with the ingot after casting until further processing. 
     
     
       8. The method of  claim 1 , wherein the source material is selected from the group consisting of titanium, zirconium, niobium, tantalum, hafnium, nickel, and alloys thereof. 
     
     
       9. The method of  claim 1 , where in the outer pipe is selected from the group consisting of steel, copper, and ceramics. 
     
     
       10. The method of  claim 1 , wherein the source material is fed into the mold cavity at substantially the top of the mold. 
     
     
       11. The method of  claim 1 , further comprising providing a receiver holding the mold center to prevent lateral movement of the mold center during casting. 
     
     
       12. An apparatus for semi-continuous casting of hollow ingots comprising:
 a mold center having an inner pipe and an outer pipe arranged to form an annular space for a cooling medium, the mold center being configured to move progressively downward through the apparatus during casting of the hollow ingot; 
 an outer mold which is configured to provide a mold cavity between the mold center and said outer mold; 
 a heating device configured to heat a top surface region of said mold cavity and 
 a puller for moving the mold center downward relative to the outer mold. 
 
     
     
       13. The apparatus of  claim 12 , wherein the outer pipe is consumable and remains with the ingot until further processing. 
     
     
       14. The apparatus of  claim 12 , wherein the puller comprises a hole arranged to receive the mold center. 
     
     
       15. The apparatus of  claim 12 , wherein the puller locks the mold center in place. 
     
     
       16. The apparatus of  claim 12 , the heating device comprises one or more electron beam guns, an electroslag remelting apparatus, a plasma arc apparatus, or one or more plasma torches. 
     
     
       17. The apparatus of  claim 12 , further comprising a receiver located above the mold center and arranged to prevent lateral movement of the mold center during casting.